Tire Modelling

The work involved the study of phenomena of standing waves in tires, with the consideration of contact area. It is well known fact that the visible deflections are generated when the vehicle speed is larger than a certain critical speed. In literature this term is coined as Critical Speed. It is the speed at which circumferential waves initiate which appear stationary in the frame which is moving with the tire and is fixed to tire axis; they appear for an external observer as stationary, or standing waves. The visible deflections are formed on tires behind the area of road-tire contact at high rolling speeds with detrimental effects on tire. Due to complex structure of tires, it is difficult to incorporate all the aspects in the simulation or analytical studies. Tire is a robust part with a very complex construction, which makes it hard to model.

                                                                                                                                        Standing waves phenomena in tires

It has been extensively studied by various researchers and modelled using various methods. Tire modelling requires tire interaction with the road/pavement, which can be condensed down to the contact problem. This problem has been modelled in various ways, some models include resonance phenomena, some models include wave propagation theory. In the study, the effect of contact was taken into consideration. To simplify the problem, a linear visco-elastic ring was considered to be in contact with the rigid foundation. It included the analysis of the standing waves in tires and the behavioural changes at the critical speed, and modelling tires as a visco-elastic ring and deriving analytical results in MATLAB.

It was further taken to a new level by modelling the actual tire models. The CAD part obtained from the supplier, meshing done in Hypermesh and solver used was ABAQUS. But due to difficulty in incorporating all the aspects of the tires and its complicated architecture, it is nearly impossible to model the actual tires. 

                                                        The images below show the CAD model, The FEM model and the cut section of the tire and the wheel rim. 

The experimental tests were carried out to match the analysis. The energy dissipation factor was calculated from the ABAQUS analysis and it was compared with the experimental results, which came in close resemblance with each other.